Technical swimming paddle for assisted stroke execution

ABSTRACT

A technical swimming paddle for assisted stroke execution consists of two generally planar elements connected by a longitudinal fold that only admits movement of said elements when pressure is exerted from the side corresponding to the back of the hand, while locking them into aligned co-planar configuration when pressure is exerted from the opposite (palmar) side. The connecting device is specifically designed so that movement of the adjoining elements disrupts the swimmer’s ability to hold and utilize the paddle, therefore discouraging the application of pressure from the direction associated with the back of the hand, and serving as real-time feedback on the potential presence of said pressure during stroke execution. In this manner, the device allows users to fine-tune stroke execution towards optimization of their swimming technique.

FIELD OF THE INVENTION

This invention relates to the field of stroke optimization for advanced swimmers. More specifically, it provides real-time feedback for estimating and optimizing flow-pattern efficiency around the hand.

BACKGROUND OF THE INVENTION

Typical swimming strokes can be subdivided into five phases: entry, catch, pull, push and recovery. Although said phases differ in the prescribed position of the hand with respect to surrounding water, they all share one common principle: pressure against the water should be consistently minimized on the dorsal side of the hand. For example, contemporary front-crawl technique, for which the technical paddle is best suited, prescribes that the hand should enter the water with minimal resistance and, before progressing on to the catch phase, it should be oriented so that the palm is approximately parallel to the surface of the water. This arrangement ideally envisages minimal pressure from either side (dorsal or palmar) of the hand against water.

The catch phase marks the transition from the entry configuration onto one where the hand is nearly orthogonal to the water surface, setting the stage for an efficient pull phase. During this transition, a primary challenge is to avoid pressure against the dorsal side of the hand; this scenario can occur if the catch is initiated prematurely, thus generating drag that works against the forward glide associated with the entry phase.

During both pull and push phases, the hand must ideally lock in place and act as pivot by exerting maximal pressure against the palmar side, moving the swimmer forward by swiveling the arm around the hand. Except for the inevitable pressure that may be exerted by turbulence on the dorsal side of the hand, all forces coming from this side should be minimized to avoid displacing the hand in the direction opposite to that intended by the swimmer.

The final phase involves recovery to the entry phase. Similar to the catch phase, the recovery phase involves a delicate transition during which the hand is disengaged from pushing against the palmar side and is brought back into forward gliding configuration, ready for entry. If enacted prematurely, recovery causes water to exert pressure on the dorsal side of the hand. The resulting drag not only slows down forward propulsion, but also serves to destabilize correct reorientation of the hand.

When looking to improve their technique, swimmers consistently attempt to monitor flow pattern around their body (including the hand), either implicitly or explicitly. However, water flow surrounding the hand and body is exceedingly difficult to monitor accurately via somatosensory perception due to the saturating stimulation produced on the skin by the swimming action. As for monitoring absolute hand orientation per se (e.g. in relation to water surface orientation), this is challenging to achieve in the absence of stable visual cues (for example when executing front crawl), and proprioception is prohibitively poor when floating in water. For these reasons, swimmers can greatly benefit from devices that provide them with real-time feedback on correct placement/dynamics of the hand throughout the stroke cycle. The present invention is intended for such purpose, while at the same time retaining mechanical simplicity without involvement of sophisticated measuring components (e.g. accelerometers).

Previous patents aimed at aiding swimmers in stroke execution have rarely incorporated moving elements of any kind. The large majority of swimming hand paddles is designed around the principle of shaping a single rigid element so that it either reduces or enhances drag around the hand as a function of stroke mechanics (e.g. U.S. Pat. No. 28,855, U.S. Pat. No. 4,913,418, U.S. Pat. No. 7,179,146 B2, U.S. Pat. No. 5,147,233, U.S. Pat. No. 5,511,998, U.S. Pat. No. D837,327 S, U.S. Pat. No. D748,752 S, U.S. Pat. No. 10,894,187 B2, U.S. Pat. No. D880,635 S, U.S. Pat. No. 10,549,169 B2, U.S. Pat. No. 10,518,135 B2, U.S. Pat. No. D864,331 S, U.S. Pat. No. D823,417 S, U.S. Pat. No. 10,022,608 B2, U.S. Pat. No. 9,931,541 B2, U.S. Pat. No. 9,717,953 B1, U.S. Pat. No. 8,496,506 B2, U.S. Pat. No. 7,566,252 B2, U.S. Pat. No. 7,494,395 B2, U.S. Pat. No. 7,147,526 B1, U.S. Pat. No. 7,125,299 B1, U.S. Pat. No. 6,019,650, U.S. Pat. No. 5,842,896, U.S. Pat. No. Des. 397,187, U.S. Pat. No. 5,651,710, U.S. Pat. No. Des. 378,307, U.S. Pat. No. 5,516,319 U.S. Pat. No. 5,376,036, U.S. Pat. No. Des. 318,894, U.S. Pat. No. 5,288,254, JP 3215059 U, JP 2014-73191 A, U.S. Pat. No. 9,308,418 B2, U.S. Pat. No. 1,546,670, U.S. Pat. No. 1,717,026). Because the aid takes on a rigid shape, it does not dynamically respond to water flow by modifying its configuration. As such, it is incapable of providing a targeted estimate of water flow pattern around the hand that is conveyed to swimmers via obvious configural changes. Furthermore, with a few exceptions (U.S. Pat. No. 5,288,254), those inventions are generally designed to aid swimmers in the execution of only the pull phase, namely that portion of the stroke cycle during which the hand is oriented perpendicularly to the direction of movement and is used to propel the swimmer forward.

Other relevant technical aids have occasionally incorporated moving elements, but of an entirely different nature and/or with unrelated objectives. The moving flap attached to the paddle disclosed in U.S. Pat. No. 8,585,453 B2, for example, is designed to produce additional drag during the pull phase when the swimmer executes this movement incorrectly. Although this device presents some shared goals with the invention disclosed herein, it differs substantially both in design and in its capability to respond to flow pattern around the hand: to mention one difference, it does not respond to pressure applied to the back of the hand. Furthermore, it does not provide direct feedback to the swimmer, but rather indirectly via increased drag.

A different approach has been to maintain rigidity of the paddle, yet enhance its monitoring capabilities via electronic sensors that measure parameters such as orientation and acceleration of the hand (e.g. U.S. Pat. No. 10,080,922 B2, U.S. Pat. No. 3,952,352, U.S. Pat. No. 2017/0043212 A1, U.S. Pat. No. 2017/0128808 A1, U.S. Pat. No. 2019/0021616 A1). Said sensors are costly, involve data storage and digital processing, and are not designed to specifically monitor water flow. Because the relationship between sensor-relayed parameters and water flow pattern around the hand is of an indirect nature, this approach does not provide effective monitoring of said pattern.

There is an additional class of devices which, upon cursory inspection, may appear related to the present invention: hinged paddles (e.g. U.S. Pat. No. 2,017,463, U.S. Pat. No. 2,389,196, U.S. Pat. No. 5,647,783, U.S. Pat. No. 5,304,080). The critical difference between those devices and the present invention is that, in the case of previous devices, the hinged section is designed to serve a useful purpose, rather than a potentially disruptive role under incorrect stroke execution (as is the case for the present invention). Consider for example U.S. Pat. No. 1,541,100 (see also U.S. Pat. No. 5,304,080, US Pat. No. 2,389,196, U.S. Pat. No. 2017/0232303 A1, U.S. Pat. No. 2018/0001147 A1 for related examples): this paddle is designed so that it can bend around a hinge oriented orthogonally to the direction of movement, and in so doing assumes a concave shape analogous to the configuration that may be obtained with flexible paddles (e.g. U.S. Pat. No. 6,899,581 B1, U.S. Pat. No. 4,746,313, U.S. Pat. No. 4,067,081, U.S. Pat. No. 3,938,207, EP 2,543,417 A1). In said design, the hinge is intended as a flexible element that should be exploited by swimmers to aid their efficiency. Similarly, U.S. Pat. No. 2,017,463 presents two lateral flaps that only fold when flow pressure is applied to the dorsal portion of the hand, and not to the palmar side, similar to the present invention (see also U.S. Pat. No. 4,756,699, U.S. Pat. No. 4,316,300, JP 2015-181793 A for related designs attached to the forearm). In U.S. Pat. No. 2,017,463, however, the folding elements are intended for positive exploitation by the swimmer in order to carry the paddle back to its starting position before executing another pull: they are designed to reduce resistance of hand movement through water during the recovery phase of the stroke cycle. Furthermore, the principle behind U.S. Pat. No. 2,017,463 is only applicable in the restricted case of non-technical swimming style, in which the recovery phase is performed by simply executing the pull phase in reverse fashion. This approach is never utilized during technical swimming in conformity with contemporary practice (as described above). Similar considerations apply to U.S. Pat. No. 1,663,328 and U.S. Pat. No. 1,708,331.

OBJECTS OF THE INVENTION

The objective of the present invention is to equip swimmers with a paddle which, when used incorrectly, readily changes configuration so as to become ineffective/unusable, and does so in a manner that is immediately obvious to swimmers. This real-time feedback can then be exploited by swimmers to adjust their stroke execution in an effort to maintain the paddle in its stable configuration, a process that aligns with correct swimming technique. More specifically, whenever water pressure is applied to the dorsal side of the paddle, the device folds and/or separates into two elements, thus becoming a useless source of hindrance. On the contrary, when water pressure is applied to the palmar side, the paddle retains its flat rigid shape. During correct execution of the stroke cycle, pressure should only be applied to the palmar side of the paddle; under such conditions, swimmers would experience the present invention as no different than regular rigid paddles. During incorrect execution, however, movement of the hand almost invariably results in substantial pressure being applied to the dorsal side; under this scenario, swimmers are made immediately aware of the incorrect nature of their stroke technique by the evident loss of paddle functionality.

Other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.

SUMMARY OF THE INVENTION

In the essence of one inventive subcombination, the technical hand paddle comprises: one left planar or nearly planar element of trapezoidal or rectangular shape with rounded edges, referred to herein as “left plate”; one right planar or nearly planar element of trapezoidal or rectangular shape with rounded edges, not necessarily identical to the left plate, referred to herein as “right plate”; a longitudinal mechanism connecting said plates in such a fashion that they remain connected and parallel when fluid pressure is applied from one side of the plates in the direction perpendicular to the orientation of the plates, but become disconnected when fluid pressure is applied from the opposite side.

In the essence of a second inventive subcombination, the technical hand paddle comprises: the left and right plates detailed above; a longitudinal mechanism connecting said plates in such a way that they remain connected and parallel when fluid pressure is applied from one side of the plates, but fold when fluid pressure is applied from the opposite side.

In the essence of a third inventive subcombination, the technical hand paddle comprises: the left and right plates detailed above; an adjustable longitudinal mechanism connecting said plates in such a way that they remain connected and parallel when fluid pressure is applied from one side of the plane, but fold or become disconnected when fluid pressure is applied from the opposite side, and such that the mechanism can be adjusted with regard to the amount of pressure that causes the plates to fold or become disconnected.

It is a general objective of the present invention to provide swimmers with a hand paddle for strength-training that also prevents improper technique by changing configuration under the effect of water pressure patterns that are inconsistent with correct technical execution.

It is more particularly an objective of the present invention to provide swimmers with immediate feedback regarding the occurrence of incorrect stroke execution, so that swimmers can adjust said execution in real time.

Yet another particular objective of this invention is to achieve the above-stated goals via simple mechanical means that can be easily incorporated into a cost-effective design that is also robust and durable.

A further objective of this invention is to achieve the above-stated goals by means of an appealing design that is not too dissimilar in appearance from regular paddles, so that swimmers are not discouraged from utilizing it by cumbersome design or appearance that attracts unwanted attention.

Other objectives, features and advantages of the invention disclosed herein will be apparent from the drawings and detailed description below.

BRIEF DESCRIPTION OF DRAWINGS

Referenced features of disclosed invention are illustrated in FIGS. 1, 2, 3, 4, 5 and 6 . Additionally, FIGS. 7A, 7B, 8A, 8B, 9, 10A, 10B, 11, 12A, 12B, 13 and 14 reproduce photographic images of 3D-printed artefacts incorporating the principles and specifications illustrated in the preceding Figures.

FIG. 1 illustrates the basic principle behind the swimming paddle (for left-hand only) viewed from the dorsal side (top) and from the front side (bottom).

FIG. 2 demonstrates the manner in which the two halves of the paddle are intended to fold and disconnect from each other when water pressure is applied from the dorsal side.

FIG. 3 demonstrates the manner in which the two halves of the paddle do not fold and remain connected when water pressure is applied from the palmar side.

FIG. 5 depicts a specific implementation of the mechanical specification demonstrated in FIGS. 1-3 , where the two halves of the paddle are connected via an interlocking device.

FIG. 4 depicts the right half of the paddle in FIG. 5 , while FIG. 6 depicts the left half, viewed from 4 different angles (dorsal, left-lateral, right-lateral, front sides).

FIG. 7A is a photographic image of a physical 3D realization of the disclosed invention, printed according to the specifications in FIGS. 4-6 , where the two halves of the paddle are detached.

FIG. 7B is a photographic image of the physical 3D realization displayed in FIG. 7A, where the two halves of the paddle are attached.

FIG. 8A demonstrates how the 3D artefact in FIG. 7A is capable of implementing the mechanical principle outlined in FIG. 3 . In this demonstration, pressure is applied to the palmar side of the artefact by the supporting steps to the left and right sides of the artefact as a result of gravity.

FIG. 8B demonstrates how the 3D artefact in FIG. 7A is capable of implementing the mechanical principle outlined in FIG. 2 . In this demonstration, pressure is applied to the dorsal side of the artefact by the supporting steps to the left and right sides of the artefact as a result of gravity.

FIG. 9 demonstrates how the 3D artefact in FIG. 7A is fitted to the hand, viewed from four different angles, alongside its folded configuration (bottom photograph).

FIG. 10A illustrates one possible device for regulating folding compliance of the artefact.

FIG. 10B illustrates another possible device for regulating folding compliance of the artefact.

FIG. 11 is a photographic image of two physical 3D realizations of the artefact, one for the left hand and one for the right hand.

FIG. 12A demonstrates how the two artefacts in FIG. 11 may be stowed away in compact fashion.

FIG. 12B demonstrates how the two artefacts in FIG. 11 may be placed on a resting surface in compact fashion.

FIG. 13 contains photographic images of a physical 3D realization of the disclosed invention, printed according to specifications that differ slightly from those depicted in FIGS. 4-6 . In this realization, the interlocking device connecting the two halves of the paddle presents two protruding elements, rather than three as in FIG. 7A.

FIG. 14 contains photographic images of a physical 3D realization of the disclosed invention, printed according to the specifications in FIGS. 4-6 but modified to incorporate ergonomic principles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The design principle underlying the present invention is summarized in Fif. 1-3. We refer to different views/sections of the inventive device with reference to the hand applied to the device, the hand extended forward with its palmar side parallel to the ground, as demonstrated in FIG. 1 : front is where fingers point, back is on the opposite side; bottom is the region located under the palm of the hand; top is the region located above the dorsal part of the hand; lateral refers to left and right sides of the paddle (respectively right and left sides in FIG. 1 ); longitudinal (or sagittal) plane is oriented back to front perpendicular to the plane defined by the extended hand. Following this convention, the top part of FIG. 1 depicts a top view of the invention with hand placed as intended, while the bottom part of FIG. 1 depicts the corresponding front view. When pressure is applied to the bottom of the inventive device, it is produced by water-flow directed upward; when it is applied to the top, it is produced by water-flow directed downward. We also use the term “dorsal side” and “palmar side” to refer to top and bottom sides respectively.

The hand paddle is divided longitudinally (along the sagittal plane) into two separate elements (1-2), not necessarily of equal size or shape, and not necessarily planar. Said elements are depicted as symmetric and planar in FIG. 1 , but neither symmetry nor planarity are necessary features of the invention. The two elements are connected in such a way that they assume the shape of a regular swimming paddle (FIG. 1 ). When water pressure is applied to the bottom (palmar) side of the paddle (FIG. 3 ), the two elements retain their paddle-like configuration. When water pressure is applied to the top (dorsal) side (FIG. 2 ), the two elements fold towards the palmar side and fail to retain the original shape depicted in FIG. 1 . The two elements may or may not separate from each other in the process of folding, however in either case it is intended that this configural change should be disruptive to the swimmer, and therefore actively avoided by the swimmer. This specific characteristic sets the present invention apart from related inventions containing hinges (U.S. Pat. No. 2,017,463, U.S. Pat. No. 2,389,196, U.S. Pat. No. 5,647,783, U.S. Pat. No. 5,304,080, U.S. Pat. No. 1,663,328 and U.S. Pat. No. 1,708,331, U.S. Pat. No. 1,541,100, U.S. Pat. No. 5,304,080, U.S. Pat. No. 2,389,196, U.S. Pat. No. 2017/0232303 A1, U.S. Pat. No. 2018/0001147): in those prior disclosed specifications, relative movement of separate elements constituting the paddle is intended for the purpose of reducing drag during the recovery phase of a paddle stroke that is performed under water. Therefore, in those prior disclosed specifications, the presence of hinges and their engagement during stroke execution is intended as an aiding feature which swimmers are encouraged to utilize by design. Said principle is opposite to the one adopted for the design of the invention disclosed herein, for which configural changes of the connecting mechanism (such as folding and/or detaching) are intended to specifically disrupt the user’s ability to hold the paddle and/or swim with it, whether the mechanism is implemented in the form of a hinge, a hinge-like structure, or the structure detailed further below (see FIGS. 4-6 ), or any other structure that serves an equivalent purpose. It should also be noted that most of the prior disclosed inventions containing hinges, with few exceptions (e.g. U.S. Pat. No. 2017/0232303 A1, 8,585,453 B2), are designed for application to stroke movements that are not prescribed by contemporary swimming technique: except for breaststroke, all other strokes prescribe arm recovery movements above water surface and through air.

The mechanical principle depicted in FIGS. 1-3 may be implemented using different embodiments. FIGS. 4-6 demonstrate one such embodiment consisting of interlocking elements (4,5,6,8,9,10) that serve two primary purposes: implementation of the mechanism depicted in FIGS. 1-3 ; introduction of holding element whereby said element is to be inserted between two fingers, for example the index and middle fingers, so that the paddle may be held close to the palm during the swimming action (FIG. 5 ). In this embodiment, the paddle consists of two separate elements (1,2), following the design introduced in FIGS. 1-3 . Each element is constructed from 5 sub-elements: a plate (1,2), a ridge (3,7), three teeth protruding in alternate fashion towards left and right sides (4,5,6,8,9,10). Below we illustrate the embodiment for the paddle associated with the left hand (FIGS. 4-6 ). The paddle associated with the right hand is identical, except it is mirror symmetrical around the sagittal plane (FIG. 11 ).

The right element of the paddle (FIG. 4 ) consists of a plate (1) oriented parallel to the hand (as demonstrated in FIG. 5 ). A suitable choice of dimensions for the plate would be 15.0 cm×10.0 cm×0.5 cm (length×width×thickness), however it is envisaged that slightly different values may serve equally well. The plate may be shaped in the fashion of a trapezoid with rounded edges, however it is envisaged that other shapes may serve equally well provided they do not depart excessively from the area occupied by the swimmer’s hand. A ridge (3) extends from the plate, such that the face of the ridge is orthogonal to the plate and the orientation of the ridge is along the longitudinal direction (FIG. 4 ). A suitable choice of dimensions for the ridge would be 7.0 cm×2.5 cm×0.3 cm (lengthxheightxthickness), however it is envisaged that slightly different values may serve equally well. Three rectangular sub-elements (4,5,6), herein referred to as teeth, protrude from the top of the ridge so that said teeth are parallel to the plate (FIG. 4 ). Two teeth (4,6) extend towards the right side of the paddle, while the remaining tooth (5) extends towards the left side (FIG. 4 ). A suitable choice of dimensions for the two teeth protruding rightward would be 2.5 cm×2.0 cm×0.3 cm (length×width×thickness), however it is envisaged that slightly different values may serve equally well. A suitable choice of dimensions for the tooth protruding leftward would be 2.5 cm×2.2 cm×0.3 cm (length×width×thickness), however it is envisaged that slightly different values may serve equally well, provided they are such that the lateral (left-to-right) extent of this sub-element exceeds the lateral extent of the other teeth by an amount approximately equal to the thickness of the ridge. Furthermore, said tooth (5) is upper-offset with respect to the other two teeth (4,6) along the height of the ridge (3), as illustrated in FIG. 4 . The size of said offset is approximately equal to the thickness of the teeth, which is best specified to be equal for all three.

The left element of the paddle (FIG. 6 ) is similar in structure and size to the right element detailed above. It consists of a plate (2) oriented parallel to the hand (as demonstrated in FIG. 5 ). A ridge (7) extends from the plate, such that the face of the ridge is orthogonal to the plate and the orientation of the ridge is along the longitudinal direction (FIG. 6 ). Three teeth (8,9,10) protrude from the top of the ridge so that said teeth are parallel to the plate (FIG. 6 ). Two teeth (8,10) extend towards the right side of the paddle, while the remaining tooth (9) extends towards the left side (FIG. 6 ). A suitable choice of dimensions for the two teeth protruding rightward (8,10) is such that their width equals the width of the leftward-directed tooth (5) protruding from the right element (1). A suitable choice of dimensions for the tooth protruding leftward (9) is such that its width is equal to the width of the rightward-directed teeth (4,6) protruding from the right element (1). Furthermore, the leftward-directed tooth (9) is lower offset with respect to the other two teeth (8,10) along the height of the ridge (7), as can be seen most clearly in FIG. 6 . The size of said offset is approximately equal to the thickness of the teeth, which is best specified to be equal for all three and should be equal to the thickness of the teeth (4,5,6) protruding from the left element (1).

As demonstrated in FIG. 5 , the above-detailed elements are interlocked so that the rightward-directed teeth (8,10) protruding from the left plate (2, FIG. 6 ) are inserted immediately above the rightward-directed teeth (4,6) protruding from the right plate (1, FIG. 4 ), while the leftward-directed tooth (5) protruding from the right plate (1, FIG. 4 ) is inserted immediately above the leftward-directed tooth (9) protruding from the left plate (2, FIG. 6 ). When inter-locked in this manner, right (1) and left (2) elements are juxtaposed so that their ridges (3,7) come into contact (FIG. 5 ); the resulting longitudinal ridge (3+7), combined with the interlocked teeth protruding laterally on both sides from the top of the ridge, can function as paddle-holder for two fingers inserted under the protruding teeth (FIG. 5 ). When held this way, the two ridges remain juxtaposed during correct execution of a stroke, however the force produced by this gripping action is not sufficient to prevent the two elements from folding towards the palmar side when water pressure is applied onto the dorsal side during incorrect execution.

In the embodiment depicted in FIGS. 4-6 , the edge of each plate immediately under the ridge presents a slanted profile (11,12) running along the longitudinal extent of the plate. This feature is introduced to facilitate folding of the plates during incorrect stroke execution (see also FIG. 8B), but it is not critical to the proposed design.

As demonstrated in FIG. 5 , the above-detailed interlocking mechanism allows palmar folding (13,14) of the two paddle elements (1,2) which, as a consequence of said folding action, assume a configuration (17,18) that hinders paddle functionality. The interlocking mechanism, however, does not permit folding in the opposite direction (15,16), thus implementing the principle outlined in FIGS. 1-3 .

The above detailed interlocking design, or variations upon it that retain the same function in their essence and purpose, can be readily augmented by the addition of simple devices that allow users to vary the amount of pressure required to produce folding/detachment. One possible and cost-effective implementation of said augmentation is illustrated in FIG. 10A and FIG. 10B. Here, the two ridge elements (3,7) are fastened by means of one or more elastic bands, with the number and position of the bands producing differing degrees of resilience to folding. As a way of example, FIG. 10A demonstrates the application of a single band (19) attached to the lower part of the two ridges; this configuration confers a small amount of resilience to folding, thus serving primarily the purpose of retaining integrity of the paddle when not in use. For example, when the paddles are placed at the edge of the pool for later use, the presence of a single band (19) ensures that they are already assembled in their intended configuration. Furthermore, and in combination with the mirror symmetry associated with the two paddles for the different hands (FIG. 11 ), the connection provided by the elastic band allows for the two paddles to be interlocked and stowed away as one unit, as demonstrated in FIG. 12A. The application of two bands (19,20), one attached to the lower part of the ridges (19) and one attached to the upper part of the ridges (20), provides greater resilience to folding. This configuration (demonstrated in FIG. 10B) would be appropriate for less expert swimmers, who may find it difficult to operate the paddles in the original configuration.

The above detailed disclosure is intended as only illustrative of the preferred embodiment of, and not a limitation upon the scope of, the disclosed invention. Those skilled in the art will envision many other possible variations of the structure disclosed herein that nevertheless fall within the scope of the following claims. For example, it is conceivable that the planar elements of one paddle may be shaped in a slightly different manner than detailed above for the purpose of optimizing efficiency or incorporating ergonomic principles (U.S. Pat. No. 7,267,595 B1 and U.S. Pat. No. 5,643,027, U.S. Pat. No. D789,475 S, U.S. Pat. No. 9,492,712 B2, U.S. Pat. No. D890,283 S), and/or that said elements may be differ between themselves to accommodate the asymmetric shape of the hand (FIG. 14 ), and/or that the elements associated with left and right hands may be shaped differently to accommodate the mirror symmetry of the two hands (FIG. 11 ). It is also conceivable that straps, clips or the like may be introduced to bind one or more fingers, or other parts of the hand and/or wrist, to the paddle elements. These may be either flexible or essentially rigid. It is further conceivable that the connecting mechanism may be realized using more or less interlocking elements (see FIG. 13 for an example), or by means of a modified design which nevertheless incorporates the same mechanical principle (FIGS. 1-3 ). Additionally, it is envisaged that a band, strap or the like may be introduced to maintain loose connection between the two planar elements under the configural change effected by pressure from the dorsal side, so that they do not separate completely (similar to 19 in FIG. 10A). Furthermore, it is envisaged that a mechanism for regulating compliance of the paddle to folding may be implemented using designs that are different from those exemplified by FIG. 10A and FIG. 10B, such as adjustable screw-like devices, springs, sliding/extendable brackets, or magnetic elements. It is also envisaged that one or both plates may be modified with the addition of perforated sections as is commonly observed in swimming paddle designs (e.g. U.S. Pat. No. 9,931,541 B2, U.S. Pat. No. 9,492,712 B2, U.S. Pat. No. 5,147,233, U.S. Pat. No. 7,179,146 B2, U.S. Pat. No. 7,147,526 B1, U.S. Pat. No. 6,019,650, U.S. Pat. No. 5,651,710). Accordingly, the scope of the invention should be determined with reference to the appended claims, and not by the examples given above.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, because certain changes may be made in carrying out the above method and in the construction(s) set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. 

What is claimed:
 1. A technical swimming paddle comprising: a. two generally planar elements, herein referred to as ‘plates’; b. a mechanism connecting said elements along the longitudinal direction, such that the two plates remain parallel when pressure is applied from one side orthogonal to the plates, and fold towards said side when pressure is applied from the opposite side; c. a holding device that allows the user’s hand to hold the two connected plates so that the palm of the hand is parallel to said elements and rests on the side of said elements upon which pressure causes folding of said elements.
 2. The technical swimming paddle of claim 1, wherein the two plates are planar and mirror symmetric in shape.
 3. The technical swimming paddle of claim 1, wherein the surface of each plate departs from planarity so as to accommodate anatomical structures of the hand, such as the thenar eminence and the pisiform (region immediately above the wrist).
 4. The technical swimming paddle of claim 1, wherein one or both plates are perforated at one or more locations to ease water flow.
 5. The technical swimming paddle of claim 1, wherein one or both plates present fin-like protrusions along one or more edges, for the purpose of stabilizing the paddle during the entry phase.
 6. The technical swimming paddle of claim 1, wherein the two plates are not mirror symmetric in shape, each plate being shaped so as to mimic the anatomical asymmetry of the hand.
 7. The technical swimming paddle of claim 1, wherein the holding device detailed at c depends from the connecting mechanism detailed at b.
 8. The technical swimming paddle of claim 1, wherein the holding device detailed at c depends from one or both plates detailed at a.
 9. The technical swimming paddle of claim 1, further comprising holding devices depending from one or both plates in the form of permanent fixtures protruding from the plates, or in the form of temporary fixtures such as bands and/or straps.
 10. A technical swimming paddle comprising: a. two generally planar elements, herein referred to as ‘plates’; b. a mechanism connecting said elements along the longitudinal direction via interlocking sub-elements, herein referred to as ‘teeth’, such that the two plates remain parallel when pressure is applied from one side orthogonal to the plates, and fold towards said side when pressure is applied from the opposite side.
 11. The technical swimming paddle of claim 10, further comprising a holding device that allows the user’s hand to hold the two connected plates so that the palm of the hand is parallel to said elements and rests on the side of said elements upon which pressure causes folding of said elements.
 12. The technical swimming paddle of claim 10, further comprising an adjustable mechanism that regulates the folding compliance of the connecting mechanism detailed at b, in the form of strings, straps, screws, magnetic elements or other similar devices that serve the same functional scope.
 13. A technical swimming paddle comprising: a. two generally planar elements, herein referred to as ‘plates’; b. a hinge, connecting said elements along the longitudinal direction, such that the two plates remain parallel when pressure is applied from one side orthogonal to the plates, and fold towards said side when pressure is applied from the opposite side.
 14. The technical swimming paddle of claim 13, further comprising a holding device that allows the user’s hand to hold the two connected plates so that the palm of the hand is parallel to said elements and rests on the side of said elements upon which pressure causes folding of said elements.
 15. The technical swimming paddle of claim 13, further comprising an adjustable mechanism that regulates the folding compliance of the hinge detailed at b, in the form of screws, movable rods or other similar devices that serve the same functional scope.
 16. The technical swimming paddle of claim 1 and its mirror-symmetric equivalent that fits the opposite hand, further comprising embedded magnetic elements for maintaining the two paddles loosely connected when not in use, together with a method for compactly interlocking said paddles so that they remain loosely connected when not in use.
 17. The technical swimming paddle of claim 10 and its mirror-symmetric equivalent that fits the opposite hand, further comprising embedded magnetic elements for maintaining the two paddles loosely connected when not in use, together with a method for compactly interlocking said paddles so that they remain loosely connected when not in use.
 18. The technical swimming paddle of claim 13 and its mirror-symmetric equivalent that fits the opposite hand, further comprising embedded magnetic elements for maintaining the two paddles loosely connected when not in use, together with a method for compactly interlocking said paddles so that they remain loosely connected when not in use. 